Parallelogram
A parallelogram is a flat shape with opposite sides parallel and equal in length.
- Opposite sides are parallel
- Opposite sides are equal in length
- Opposite angles are equal (angles A are the same, and angles B are the same)
- Angle A and angle B add up to 180°, so they are supplementary angles
Play with a parallelogram:
NOTE: Squares, Rectangles and Rhombuses are all parallelograms!
Example:
A parallelogram where all angles are right angles is a rectangle!
Area of a Parallelogram
The Area is the base times the height:
Area = b × h
Note: The height (h) is at right angles to the base (b), not the sloped side!
Example: A parallelogram has a base of 6 m and is 3 m high, what's its Area?
Area = 6 m × 3 m = 18 m2
Why is the Area base × height?
Imagine cutting off a triangle from one side and sliding it to the other side to make a perfect rectangle.
Perimeter of a Parallelogram
The Perimeter is the distance around the edges.
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The Perimeter is 2 times the (base + side length): Perimeter = 2(b+s) |
Example: A parallelogram has a base of 12 cm and a side length of 6 cm, what's its Perimeter?
Perimeter = 2 × (12 cm + 6 cm) = 2 × 18 cm = 36 cm
Diagonals of a Parallelogram
The diagonals of a parallelogram bisect each other.
In other words the diagonals intersect each other at the halfway point.
Pantograph
Based on a parallelogram, a pantograph can be used to duplicate and resize an image by tracing.
Inside Any Quadrilateral
And there's a parallelogram in any quadrilateral.